A known dual tool-carrier illustrated in DE-OS 38 31 132 A1. This dual tool-carrier consists of a main body, said main body holds a pivoted, 90.degree. truncated cone inclined at 45.degree. to the machine axis, said truncated cone supports three tool holding fixtures positioned at 120.degree. intervals star shaped and at right angles to the truncated cone surface area.
What is disadvantageous with this state-of the art is that the design can only be effected with a spur gear and is thus expensive and costly in manufacture. U.S. Pat. No. 5,149,230 illustrates and describes a dual tool-carrier for hand drills. There are two shafts provided which are flush to one another and which can be pivoted together about one axis.